The desire to produce light-weight, flexible, multi-functional composites has grown tremendously in recent years. Polymer (including elastomeric polymer) nanocomposites, in particular, have attracted attention in the past decades with the belief that they could become the next generation of high performance materials with multifunctional capabilities. One of the most compelling features of such nanocomposites is the ability to create a new class of materials with attributes that come both from the filler and the matrix. Having the ability to manipulate the degree and nature of the dispersion is key to the development of these types of novel composites. Many studies have documented enhancement of properties such as stiffness and strength, thermal stability, electrical and thermal conductivities, dielectric performance and gas barrier properties of polymer and elastomer composites with the incorporation of fillers.
Significant research has shown that carbon-based polymer nanocomposites demonstrate remarkable physical and mechanical properties by incorporating very small amounts of filler material. Owing to its extraordinary mechanical and physical properties, graphene appears to be a very attractive filler material for the next generation of smart materials in batteries, supercapacitors, fuel cells, photovoltaic devices, sensing platforms and other devices. Along with the aspect ratio and the surface-to-volume ratio, the distribution of filler material in a polymer matrix has been shown to directly correlate with its effectiveness in improving material properties such as mechanical strength, electrical and thermal conductivity, and impermeability. Unfortunately, providing good electrical conductivity while maintaining the desired qualities of the filler material has remained challenging. Similarly, the incorporation of conductive material into elastomeric polymer material has proved challenging due to the characteristics of the elastomeric filler material and the conductive material.
Although significant research has been performed to develop strategies to effectively incorporate nanoparticles into materials, the ability to control the dispersion and location of fillers to fully exploit their intrinsic properties remains a challenge, especially at the pilot and commercial scales. An alternate method for creating a connected pathway for conductive particles is to make segregated composites. The conductive particles within segregated composites are specially localized on the surfaces of the polymer matrix particles. When consolidated into a monolith, these conductive particles form a percolating three-dimensional network that dramatically increases the conductivity of the composite. Certain studies have revealed that highly conductive composites can be created when graphene is segregated into organized networks throughout a matrix material. Although the highly segregated networks provide excellent transport properties throughout the composite, they inevitably result in poor mechanical strength, since fracture can occur easily by delamination along the continuous segregated graphene phase. Since most multi-functional materials are required to provide excellent transport properties while maintaining sufficient mechanical strength, alternative methods of distributing graphene need to be developed.
Despite recent progresses on the electrical characterization of graphene-based segregated composites, no results have been yet provided regarding the combined electro-mechanical behavior of these highly conductive materials.